Question about Baby Bear stove pipe connection

[Mark in VA]

Hello,

I'm new to the forum, but there seems to be some great information here!

I recently acquired a Fisher Baby Bear, in excellent condition, and I just have a question about the stove pipe connection. I'm not new to burning wood, but I am new to the Fisher brand. With all of the other stoves I've used and installed, I've run the pipe from the thimble with the crimped or male end running down toward the stove, as not to allow creosote to run out, but since the Baby Bear seems to have a male flue collar on the back, I realize some adjustments will have to be made to do it that way.

Should I try to find some kind of double female adapter, try to crimp the 90* down enough to fit inside the collar, or just cut a short piece of straight pipe in a "coupling" type fashion to do this?

I've downloaded and read the original manual for the stove and it basically seems to give the user their option, mentioning the pro and cons of running the pipe in either direction, but I wanted to get Coaly's, as well as the other Fisher enthusiasts' opinions on this and how they have their respective stoves connected. I obviously want to do it the safest and best way possible, so any advice is appreciated.

Thanks in advance,
Mark in VA

 

[pen]

I personally like having the male end of the stove pipe connect with the stove. To make that work I added an extra crimp, and sealed the gap made from that crimp with furnace cement.

pen

 

[coaly]

Webbie mentioned in a previous post, when he crimps the male end, he gives the crimping pliers a pull to bend the end of pipe outwards to prevent the angled end. Over crimping shrinks the end to fit into the 6 inch OD outlet pipe, and the out ward flare makes the pipe end more parrellel to the inside of the flue collar for a better fit.
I've always over crimped the male end to fit it into the slightly smaller collar on the older stoves.
However.............
In the absence of crimping pliers, I found the pipe fit so tight over the collar, with a rear or side vent, I was able to drive a piece of connector pipe over the collar, seam up with a block of wood. Never had anything leak out of it, but I don't make a condenser out of my chimney either. I wouldn't do it on a top vent due to any flamable liquid possibly leaking out onto stove top. The rest of the connector pipe I install male end down. Manufacturers of pipe may differ in ID, so I don't know if I was lucky to get a good fit, or if any pipe will fit tight enough.
I noticed quite a few outlet pipes on stoves have a pipe mark on the outside of the collar where the pipe was installed over it. Must have been common practice. It may have been common to have a few black drips on the pad behind the stove as well. Not a problem to clean off tile, but unsightly when it stains brick. It does seal better on the outside with no sealer.

I believe since before the welded steel plate Fisher was invented, there were only cast iron stoves which had a cast collar sticking out that many times was even oval........... The pipe normally slid over it........ perhaps the 6 inch OD pipe used for the outlet happened to fit the pipe, and since "that was the way it was always done", there was not much thought put into it ?

 

[Mark in VA]

Thanks, Pen and Coaly for the responses.

Coaly, as you mentioned, I've noticed how tight the elbow fits over the outside of the collar on the rear of the stove, so that's why I was thinking about cutting a short piece of pipe (female on both ends) and placing that over the collar, then running the crimped ends from the flue down to that. I also have crimpers and can do it either way, I was just wondering what your opinions might be as to *best* way to run it, while maintaining a tight seal and avoiding creosote escaping at the pipe joints. I'll try hooking it up that way tonight and let you know how it goes...

Also, what type of pipe temperatures should I be trying to obtain with this little stove? The ones I've run in the past have all been larger and I've actually never used a pipe or stove thermometer in a lifetime of being around wood burning stoves, but since I'll be connecting this small stove to an 8" outside masonry chimney, I want to avoid creosote buildup as much as I can. I'm thinking seriously about adding a 6" insulated, metal lining to the flue before next winter, as well as putting a baffle in the stove, but just wanted to try it out a couple times before the warmer wheather comes in the next month or so.

Thanks again,
Mark

 

[pen]

I was just wondering what your opinions might be as to *best* way to run it, while maintaining a tight seal and avoiding creosote escaping at the pipe joints.​

If you do that, smearing some furnace cement on the collar of the stove would help the seal. Also, with a double female connection, I'd make sure there are a couple of screws in that just so it could never open up on you when the stove is running! (All joints should have 3 screws anyway, but that spot especially!)

 

[coaly]

If you're coming off the back of the stove with an elbow, I use a Tee and cap the bottom for a clean out. Mine is in the middle of a log cabin with open space behind the stove.
Try to maintain at least 250* all the way up.

 

[Mark in VA]

Thanks again to Pen and Coaly for all the advice!

I currently have the Baby Bear hooked up and burning and it's putting off some nice heat. I really like the stove so far! With three splits of seasoned oak and the front damper open about three turns or so, I'm maintaining a pipe temperature between 250* and 300 * (I have no way of monitoring the masonry flue all the way up), but so far it seems to be doing fine. It's in the mid 30's here tonight, so anymore heat is going to be a bit much for our small house. So far I've left the pipe damper completely open to allow the flue temps to remain up.

Any other advice you are willing to offer about this little stove, will be greatly appreciated.

Mark

 

[coaly]

Check out the "baffle for under $25" thread. It's the easiest and best mod you can do.
My Tee at the bottom allows any drips to run down past the outlet, and removing the cap is straight up the flue for bottom up cleaning. Picked up a Sooteater chimney cleaning whip, but need to spin it by hand with no electric!
Still works good with a brace;

 

[Mark in VA]

I'm actually planning to stop by a local welding shop this afternoon on my way home to get a steel plate for the baffle and hopefully get it installed per your recommendations this weekend. It sounds like an excellent idea!

As far as the pipe connection, I went ahead and just ran an elbow off the rear of the stove, then up to a second 90*, where a full 24" horizontal piece exits into the clay thimble for the masonry flue. So far everything seems to be working fine and for such a small stove, the Baby Bear really throws some heat!

While burning it last night, I tried to maintain pipe temps between 250 - 350 and that allowed me to keep things comfortable in the house. Any more would have run us out, but since I'm new to using a pipe thermometer, is this a good range for this stove on an 8" outdoor masonry chimney? (The thermostat is located about 18 - 20 inches above the stove on single wall 24 ga. pipe.)

For all the years I've burned wood, I guess you could say I've just winged it and burned the other stoves where they felt comfortable for house temperature and/or overnight burns, then let them run good and hot for a while, at least once a day, to burn off any buildup. I've also always strived to burn dry hardwood thats been split and stacked for at least a year, if not more. Being a former volunteer firefighter, and having run my fair share of chimney fires, I try to be careful and check the chimney frequently. I've never had a creosote problem with this flue in past, but now, actually watching the thermostat makes me a little paranoid when it starts to drop toward the lower zone...

Also, what range of stove top temps should I be looking for with the Baby Bear?

 

[CamFan]

the way that the baby, mama, and papa was to be hooked up was with a dura vent 1672 double skirted adapter. It slides right over the 6" OD pipe (on the stove) and the male end (of the pipe) fits right in the adapter to allow creosote to run back into the stove. Dura vent has a 1872 double skirted adapter for 8" pipe or gma and gpa. Some of the later stoves had 1/4" wall pipe and they were either 6"ID or 8" ID which eliminated the need for the adapter. Double crimping etc is not the correct method. Good luck

 

[Mark in VA]

Thanks, CamFam! I will definitely look into getting one of those. That's basically a pre-fabricated version of what I was referring to as a "coupling". I was just going to make one by cutting a short section off the female end of a piece of stove pipe, but the adapter would be a much better solution without the seam, etc.

Thanks again,
Mark

 

[CamFan]

Thanks, CamFam! I will definitely look into getting one of those. That's basically a pre-fabricated version of what I was referring to as a "coupling". I was just going to make one by cutting a short section off the female end of a piece of stove pipe, but the adapter would be a much better solution without the seam, etc.

Thanks again,
Mark

It is called an adapter when you look around. If you can not find one locally send me a pm. We have them but if you can find it with out shipping it would be in you best interest.

 

[Mark in VA]

Coaly,

I should be picking up my baffle for the Baby Bear this week from the welding shop (They only had 1/4" in stock and had to order the 5/16") and I had an additional question about the installation... In your original thread about the baffle, you suggest placing it on the small shelf in the rear of the stove, but mine has the larger steel plate about 5 x 10" actually touching the bottom of the flue collar. Should I still place the added baffle on this plate, or will it obstruct the flow/draft out of the collar? Or, should I try just placing it on the rear row of fire brick?

Also, earlier in this thread, you suggested keeping the pipe temperature above 250*, which I'm doing staying around 350 - 400, but what pipe temp is too high for this stove? What's optimal? The thermostat shows 550 at the upper end of the "burn zone", but in my thinking that seems like a bit much. I don't have a stove top thermostat, so I just didn't want to overfire the stove, or overheat the pipe in the rear before the baffle's in place.

Once again, I'm venting into an 8 inch exterior masonry chimney and want to avoid creosote, so I'm trying to strike a happy medium. I looked into adding a stainless steel liner, but after getting estimates and the fact that they would have to virtually tear down the existing flue (which was just recently built) to insert an insulated liner, I don't think I'll be going that route for the time being.

Anway, any and all advice you can offer is appreciated!

Mark

** As a side note, I don't know if I just have cheap thermostat or avdefective one, but it doesn't seem very consitent. It will achieve a very high temp early on and then when I try to settle in around 350 or so, it doesn't take long for it to start dropping into the lower zone. There's plenty of heat from the stove with a cracking flame behing the draft cap, but as soon as that settles down about an hour into the burn it starts to drop fairly quickly. Is this normal, or should I invest in a more quality thermostat?

 

[coaly]

I set the baffle on the plate right up to the outlet pipe. Even though it's in front of the pipe, it's on about a 45* angle so it doesn't block it off.

Thermometer will read high when starting due to kindling heating pipe, then as fire settles down igniting larger splits the heat soaks into stove, reducing flue temp. They sense a certain amount of heat from the stove top when on the front of pipe. About 275* all the way up, and not dropping below 250 anywhere in flue is what you want. If the baffle keeps it near 300 running it as you do now, that will be a good indication of how much is being directed to stove top instead of stove outlet. So bottom line is expect a 150* stove top increase and 150* pipe decrease with baffle installed at normal operating temperature.

 

[Mark in VA]

Thanks again, Coaly! That makes sense. I was thinking along the same lines as far the fluctuation in pipe temps, but I think I've read too much on these forums in the past couple weeks about the flue being oversized and have made myself paranoid... I know these stoves were originally hooked up to this size flue, if not larger, so I'm probably worrying about it too much! I've been burning wood for over 20 years, but this new thermometer has me fiddling with the draft cap constantly, trying to maintain the desired temperature, so I think I'm just going to go back to my experience and only use the thermometer as an additional point of reference. Otherwise, I'll drive myself crazy!

I'll pick up the baffle this week and let you know how things go once it's installed.

Thanks again,
Mark

 

[coaly]

You're just fine tuning it with a thermometer. It's a good thing to know what it's doing since the firebox on a Baby Bear is so small the wood load is not such a variable factor as a Mama or Papa Bear. You can't vary your output much by load. In time you'll get to know what to expect the thermometer to read, so when it doesn't read what you know it should, you know you have a change or problem.

The warnings of heating larger flues are to be sure enough heat is left to escape the stove to prevent creosote and prevent a sluggish operating stove. It can be done, it just cuts down efficiency which relates to more wood usage. If you have an unlimited supply, no big deal dollar wise. More work and shorter burn cycles is the down side. If it's your only heat source and you're away for 8 hours at a time, an insulated flue the correct size becomes necessary.

I wish I could have documented the surface temps with and without baffles with the IR, but our only heat source was a Goldilocks with factory baffle and rear heat shields for years. It was in the center of the kitchen with back facing fridge. When I put a Mama in it's place for a larger cook top, and longer log length to save cutting short for Goldi, I realized the heat that came off the stove back was too much for the fridge about 8 feet away. Milk soured in the door overnight with the new stove without a baffle, and rear shield. So I knew there was a big BTU difference radiating rearward. Since it was the only heat source and no time for measuring temperature differences, I had to get a baffle in it right away and get it fired to keep the house warm. I have that stove in an off grid log cabin now, as the sole heat source. Keeping heat away from an ice box or kerosene operated fridge starts with the baffle inside, then a movable stove shield against a large foldable clothes drying rack that is our dryer as well. Wet clothes or towles on it overnight keeps the icebox cool.
Like they say, necessity is the mother of invention.....

 

[Mark in VA]

Well, I picked up the baffle plate from the welding shop and have a couple firebricks cut on what I think is the correct angle for the install, but just wanted to confirm that my positioning of the plate is right.

The way it's setting is: Back side resting on top of the small factory baffle at the bottom of the flue collar and the front edge is pointing basically at the bottom curve of the bend where the stove top transitions from the lower portion to the upper portion. Measuring from that curve down, I got about a 2 inch gap. Does that sound about right or should it be angled steeper toward the upper portion of the stove top??

The plate is 13" x 8" and seems to fit the stove well.

Thanks,
Mark

 

[coaly]

Go for it and let us know what it does !

I don't get that fancy cutting bricks on angles. I just use pieces from cuts or broken ones and adjust the angle by sliding them fore and aft. (with the plate sitting on the corners) I only aim it towards the upper bend because I've put baffles in Mama and Papa that has a larger top that is used for cooking, and want to be able to get the upper surface really hot and be able to use the front surface for simmer of soups, stews and dutch oven.

 

[WeldrDave]

Mark, this is not a great picture but this is one I did in my baby bear, I welded in some angle iron on the side and set the plate on top of them. If you look close, I drew a line from the bottom of the flue to the lower curve.
Hope it helps.

Dave

 

[Mark in VA]

Thanks for the picture, Dave!

That's pretty much the same angle I was going with, but the picture clears it up. I haven't had a chance to actually try it out with a fire yet, but hope to in the next couple days. For now I'm just going to set the baffle on some firebrick wedges, but if it works well, I may have some angle iron welded in to support mine as well.

Mark

 

[Mark in VA]

Once again, I'd like to thank everyone for their advice about the baffle plate. It looks like it's going to work out fine, but yesterday I discovered another issue I wanted to ask the Fisher users here on the forum about. I'll appogize up front if this a little lengthy, but it's got me a concerned...

Temperatures here in VA were in the 60's yesterday, so I let the stove go out and decided to take a look inside the flue and pipe. I've only had a few fires in the stove since installing it last month and admittedly most were without the baffle, but WOW!! The stove pipe was loaded with crunchy black/brown creosote and just looking up the flue with a mirror from the cleanout, I could see what looked like about a 1/16" of hard shiny creosote, like someone had painted the inside of the clay liner with tar from the thimble to the top!! No blockages whatsoever, but from what I understand, this hard shiny film is the worst kind of creosote...

I'm burning oak that has been cut and split since last summer, and although some posters on the board would say that's not "seasoned", I've burned a whole lot worse in the past and never had a build up like this, in such a short amount of time! Is this what I should expect from this stove on an 8 inch masonry flue? I've also been keeping the pipe temperatures around 350 and stove top about 500-600* during an average burn. I have not let the stove smolder at all, even overnight, keeping visible flames behind the draft cap. At normal operating temps, there is also very minimal, if even any noticeable smoke from the flue, so I thought I was burning fairly clean.

I've burned several other stoves in the past on an identical masonry chimney (sometimes even larger ones), and even letting the fire smolder, I've never seen anything like this. At most, with the other stoves, I would get a black sooty residue inside the flue and pipe at the end of the season, most of which fell away into the cleanout below and barely needed brushing. Granted, the other stoves were larger, so maybe the extra heat kept the flue temps higher, but this really has me disheartened about the Baby Bear. I realize a 6" stainless steel liner would be best for the stove, but since the Fishers were originally connected to masonry flues, I can't see this being normal. Also as mentioned earlier, this flue was just recently built, has an excellent draw and I can't justify the cost of tearing out the clay liners to install an insulated liner at this point.

Most of my friends, family and neighbors who also burn older pre-EPA stoves, think I'm paranoid, and maybe I am, but most of these are folks who rarely ever clean their flues and burn everything from "very green" wood to trash... I grew up doing it the "old" way, but I would rather do it safely than just keeping my fingers crossed so to speak.

Anyway, I really like the little stove as it fits the room and my house perfectly, I just don't want it to be a creosote machine that I have to worry about all the time. What do y'all think?

Thanks again,
Mark

 

[coaly]

Yes, it will take a lot of heat from the smaller stove to heat the inside of a chimney that's twice the size it should be.
Burn it hot to preheat the flue before closing it down. An insulated liner stays hot inside. Your masonry chimney will draw the heat right out, even worse on the north side of a building on a windy day.

 

[WeldrDave]

Most of my friends, family and neighbors who also burn older pre-EPA stoves, think I'm paranoid, and maybe I am, but most of these are folks who rarely ever clean their flues and burn everything from "very green" wood to trash... I grew up doing it the "old" way, but I would rather do it safely than just keeping my fingers crossed so to speak.

First off, Being safe is "not paranoid" it's being responsible! I'm going to give you my "opinion" with 25+ years of burning experience. You said your burning Oak, If your wood is seasoned you "will"get some initial build up on the new pipe. When we installed our first Fisher it was all SS pipe, and we had an initial build up. BUT you answered your own question, how long have you been burning this with new pipe? Is your flue run longer? When you go outside and look at the smoke, is it clean, blue, black, or gray or white? Does the build up feel sticky? I don't mean to nit pick but but if your burning good wood, you shouldn't have that much build up unless your temps are "LOW". If what you say is your practice, your doing the right things, just keep an eye on it! And as far as Fishers being connected to masonary flues, I have seen them in every way known. I am burning a Grandma and it has had "EVERY" variety of wood in her "except pine" and I clean her out in the spring when I'm done burning, I get about 2 coffee cans full of crap that comes out, and I have my own cleaning utensiles and brush the "SIHT" out of my chimney. It sound's to me, you being new with what you have, you may be "over protective" but thats good....... It sound's like your doing things right. Look at your smoke, if your getting a nice clean/clear or crisp white, it's safe to say your OK, anything much different, check your temps and draft. I'm sure there will be more assistance coming along shortly.

 

[Mark in VA]

Dave,

Thanks for the response! Like you, I've been burning wood for a little over twenty years on my own and also grew up with wood heat in my grandparents' house (which is where my wife and I live now) and in my Dad's shop, and I have experience with a variety of stoves, just not one as small as the Baby Bear...

To give you a little more information on my setup, earlier this year, I noticed some cracks in the clay liners of the old flue that I was using and knowing that the chimney had been built in the early sixties and often doubting its' integrity prior to this, I hired a local masonry contractor to demolish the old flue and build an identical one that was up to code, etc. Unfortunately at the time, I had not read up on the values of the SS flues/liners and always considered masonry flues to be superior... Around here, many people are still burning with old unlined brick chimneys run inside of 100+ year old farm houses and even most new homes use masonry flues if the homeowner plans on burning wood from the start. You usually only see the SS flues added on as an afterthought, and I only know of a couple people who have had the liners installed after having damage and/or a chimney fire...

Anyway, it was also about this same that I came across the Fisher, and since it fit the room and my small house much better than my previous stove, I hooked it up with new pipe around the end of February, and with temperatures fluctuating around here this time of year, I've generally only burned it in the evenings, overnight and on a couple of weekends. As far as burning practices, as I mentioned, the wood was cut, split and stacked last summer and is turning gray, the bark is falling off and the ends are beginning to crack open. Slapping two pieces together gives you the crack of a baseball bat, not the dull thud of wet wood. It may not be the best, but I've seen people use a lot worse!

When I start a fire, the kindling takes right off and the new flue draws great! Once the fire is a bit more estabished, I'll add some larger splits and get the stove roaring with the draft cap about three or so turns open. To use Coaly's words in another post I read, it sounds like an "oil burner". I'll allow it to burn in this state for about 15 - 20 minutes and slowly begin to reduce the air intake. Normally, by this time the pipe thermostat has reached about 400* and I'll only back it off enough for the temp to level out around 350*. Within a few minutes, the stove top temp will begin to climb and I've found I can maintain both by turning the pipe damper to about a 2/8 position. That's pretty much where I leave it and continue to have an active, crackling flame behind the draft cap, but slow enough that it's not soaring hot. Even on overnight burns, the lowest I've set the draft cap is a full turn open and that was after the fire was well established with temps settling in the region I mentioned above.

When it comes to smoke, I'm of course seeing some on the start up, but it mostly white. A few times it seems somewhat thick, but nothing like I haven't seen before. I did however, on a couple occassions notice a hint of gray/black to the smoke, but after the stove was up to temps there was only a faint white whisp or none at all, so I figured the dark smoke was just a bit of creosote burning off.

To answer your question about the creosote that I found, what was in the pipe was like dry, brown/black flakes (about an inch or so thick) that fell right out by me knocking on the pipe outside in the yard. In the flue however, there was a shiny black glaze about an 1/16" thick. It wasn't sticky, runny or wet; just hard and shiny like black glass. Since I posted earlier, I talked to a friend who also does construction, and he seemed to think it was the new flue liner "curing"... Not sure if anyone else here has heard of that...

I also appreciate your reassurance on being paranoid vs. responsible! Hopefully, I'm worrying about nothing, but I just want to enjoy the stove and run it safely!

Mark

 

[WeldrDave]

I talked to a friend who also does construction, and he seemed to think it was the new flue liner "curing"... Not sure if anyone else here has heard of that...

I've heard of this before, but I don't have much experience with that. It seems to me your doing everything right, the only thing I can think of is that if you have an air leak somewhere. My Grandma here, the pipe comes out of the stove top 3ft, 90degree bend right in to a masonry/ terra-cotta flue.
I have "not" burned my baby yet and am really looking forward to that this fall, "I'M SURE" the hair on my neck will be standing up for a bit too... I've learned from "years" or military training that, If you've done the best you can do, followed instructions, done it correctly, asked enough questions along the way, than it's safe to say your in good shape. "but never" stop being cautious None of us want to burn our houses down. I believe you'll get in a comfort zone with the stove. I even get a little uneasy at first light off in the fall, and this stove is "WELL SEASONED" ..... Coaly and many others here are great and are a wealth of knowledge, I go back to some of the past forums and read when I can just to gather info, It's humbling to read and realize the thing's you did not know! Since I found this site, I read it every day when I can After 50+ years of age, it's amazing how much there is to learn. I think some times I'm a pain the a$$ to some but I look at it like this, if there here, and so am I, we all have something to contribute. Isn't that what this forum is all about? Never stop being safe but by what you said above, I think you OK.... Sorry about getting long winded